In fabricating semiconductor devices, titanium nitride (TiN) is generally used as a barrier metal layer for via holes or as an inorganic antireflective coating (hereinafter referred to as “ARC”) layer. For example, U.S. Pat. No. 6,133,142 to Tran et al. uses an ARC layer formed of TiN or Ti—TiN. As another example, U.S. Pat. No. 6,518,668 to Cohen uses a barrier metal layer comprising Ti or TiNx. However, TiN may be oxidized in a following process. For example, the TiN may be oxidized during an ashing process that removes photoresist. The oxidized TiN may cause an increase in contact resistance, thereby degrading operational characteristics of the device.